Topic 1 & 2 Forces & Motion Flashcards
1 Runner A finishes a race in less time than runner B. Who is faster?
runner A
2 What two measurements are needed to calculate a speed?
distance and time
3 What is the SI unit for speed?
m/s
4 What does acceleration mean?
speeding up or slowing down
5 What is a force?
push or pull
6 How do we represent forces on diagrams?
arrows, with length depending on size of force
7 What does mass mean?
amount of substance
8 What is the unit for mass?
kilogram
9 What does a vector have that a scalar does not?
direction
10 Name a scalar and a vector measured in metres.
distance, displacement
11 Name a scalar and a vector measured in metres/second.
speed, velocity
12 Name a vector with units of newtons.
force or weight
13 Is mass a vector or scalar?
scalar
14 Is energy a vector or scalar?
scalar
15 What is acceleration?
a change in velocity
16 Why is acceleration a vector?
it is measuring a change in another vector
17 What is the difference between speed and velocity?
velocity has a direction/is a vector
18 What is the equation for calculating speed?
speed = distance / time
19 What is the SI unit for speed?
metres per second
20 What is average speed?
total distance / time for whole journey
21 What is the equation for calculating distance?
distance = speed x time
22 How is a constant speed shown on a distance/time graph?
straight, sloping line
23 What does a horizontal line on a distance/time graph show?
stationary object
24 What is the speed of sound in air?
approximately 330m/s
25 How is a stationary object shown on a distance/time graph?
horizontal line
26 How can you tell which part of a journey shown on a distance/time graph has the highest speed?
steepest line
27 How can you calculate velocity from a distance/time graph?
gradient of line
28 What does acceleration mean?
change in velocity in time
29 What are the units for acceleration?
metres per second squared
30 In the acceleration equation, what does u stand for?
initial velocity
31 In the acceleration equation, what does v stand for?
final velocity
32 What is the equation for calculating acceleration?
change in velocity/time, or
33 What is the acceleration due to gravity?
10m/s2 to 1 sig. fig or 9.8m/s2 to 2 sig. fig.
34 What is the force that pulls us towards the Earth?
gravity
35 What is ‘drag’ another name for?
air resistance or water resistance
36 What are balanced forces?
forces of the same size in opposite directions
37 What do we call the forwards force produced by an aeroplane’s engine or propeller?
thrust
38 What word describes both the speed and direction of movement of an object?
velocity
39 What is the name for a single force on an object with the same effect as all the forces combined?
resultant
40 How do we describe the forces on an object when the force in one direction is bigger than the force in the other?
unbalanced
41 Two forces on an object are in the same direction. How do we calculate the resultant force?
add
42 Two forces on an object are in opposite directions. How do we calculate the resultant force?
find the difference between them
43 What does the length of a force arrow on a diagram represent?
size of force
44 An aeroplane has thrust of 2000N and drag of 1800N. What is the resultant?
200N forwards
45 Air resistance on a cyclist is 20N and friction is 5N. What is the total force trying to slow the cyclist down?
25N backwards
46 Name a vector quantity that changes as a car drives at constant speed around a roundabout.
velocity
47 What are unbalanced forces?
forces of different sizes in opposite directions
48 What is the direction of the resultant force on a car that is speeding up?
forwards
49 What is the direction of the resultant force on a bicycle that is slowing down?
backwards
50 How does a sideways resultant force affect the velocity of a moving object?
changes its direction
51 How can the pilot of an aeroplane make the plane gain speed upwards?
increase the lift/upwards force
52 How do balanced forces affect the velocity of a moving car?
The car continues with the same velocity.
53 You pedal harder on a bicycle. What happens?
you accelerate/get faster
54 H What is the name of the force that makes objects move in a circular path?
centripetal
55 H What provides the centripetal force for a car going around a roundabout?
friction
56 H What are the forces on a moon orbiting around a planet?
gravity acting towards the planet
57 H In which direction does centripetal force act?
towards the centre of the circle .
58 Why is the force of gravity greater on a lorry than on a car?
larger mass
59 Why is the resultant force accelerating a car usually less than the force provided by its engine?
air resistance and/or friction
60 Name one force that usually has to be taken into account when working out the resultant force on a moving object
drag or friction
61 When will a resultant force act to slow a car down?
when backwards forces are greater than forwards ones
62 How can friction act to make a car speed up?
between tyres and road
63 How can friction act to make a car slow down?
in brakes
64 What is the formula linking force, mass and acceleration?
F = m x a
65 An object is moving at a constant velocity. What can you say about the forces on it?
balanced
66 What is the equation relating these factors?
speed = distance / time
67 What type of force is used to slow down a moving vehicle?
friction
68 Where is this force applied?
brakes, tyres
69 Why is a wet road more slippery than a dry one?
water acts as lubricant
70 An object has a negative acceleration. What does this mean?
it is slowing down
71 What effect does drinking alcohol have on human reaction times?
slows them down/makes them longer
72 How will being tired affect reaction time?
make it longer
73 What does ?braking distance? mean?
the distance a car travels while slowing down
74 What does ?thinking distance? mean?
the distance a car travels while the driver is reacting to a danger and deciding to apply the brakes
75 How does speed affect the thinking distance?
higher speed, longer thinking distance/thinking distance directly proportional to speed
76 How does speed affect the braking distance?
higher speed, longer braking distance/braking distance proportional to speed squared
77 How does the force needed for an acceleration depend on the size of the acceleration?
larger acceleration, larger force needed
78 What does deceleration mean?
slowing down/a negative acceleration
79 H What factors affect the momentum of a moving object?
mass, velocity
80 H How does the mass affect momentum?
higher mass, higher momentum
81 H How does the velocity affect momentum?
higher velocity, higher momentum
<p>82 H What does momentum is conserved mean?</p>
<p>total momentum is the same before and after a collision</p>